Enable CI gate: fix Doxygen and add workflow.

Clear doc-block warnings so doxygen exits 0, add GitHub Actions
for host tests, Doxygen, and manual sync, and document CI in the manual.

Co-authored-by: Cursor <cursoragent@cursor.com>

Software/components/core/include/core/AudioEnhancements.hpp

@@ -21,8 +21,8 @@ namespace core {
  *
  * @dname    AudioEnhancements
  * @return   n/a (type)
- * @pubstate Mapped to PEQ bands at runtime (Chapter~\ref{ch:sigmastudio}).
- *           No dedicated SigmaStudio blocks; see \texttt{applyEnhancementsToEq}.
+ * @pubstate Mapped to PEQ bands at runtime (manual chapter sigmastudio).
+ *           No dedicated SigmaStudio blocks; see \c applyEnhancementsToEq.
  *
  * @author   Michele Bigi
  * @date     2026-07-06

Software/components/core/include/core/AudioProfileJson.hpp

@@ -55,7 +55,7 @@ namespace core {
  * @brief    serializeAudioSavedJson — success response after profile apply.
  *
  * @dname    serializeAudioSavedJson
- * @return   JSON object \texttt{\{"status":"saved"\}}.
+ * @return   JSON object with \c status set to \c saved.
  * @pubstate none
  *
  * @author   Michele Bigi
@@ -77,7 +77,7 @@ namespace core {
 [[nodiscard]] std::string serializeAudioErrorJson(std::string_view reason);
 
 /**
- * @brief    parseEnhanceLevelJson — parse POST body \texttt{\{"level":0..100\}}.
+ * @brief    parseEnhanceLevelJson — parse POST body with level 0..100.
  *
  * @dname    parseEnhanceLevelJson
  * @param    json  Untrusted request body.

Software/components/core/include/core/Bt1035At.hpp

@@ -85,7 +85,7 @@ inline constexpr std::size_t kBt1035BootInitCommandCount = 2U;
  *
  * @dname    buildBt1035AtLine
  * @param    command  Typed AT command.
- * @return   Full line including \r\n suffix.
+ * @return   Full line including CRLF suffix.
  * @pubstate none
  *
  * @author   Michele Bigi

Software/components/core/include/core/Station.hpp

@@ -59,12 +59,67 @@ public:
             std::optional<FrequencyKHz> fmFrequency,
             std::optional<PresetSlot> presetSlot);
 
+    /**
+     * @brief    name — read the preset display label.
+     *
+     * @dname    name
+     * @return   Station name value.
+     * @pubstate reads name_.
+     */
     [[nodiscard]] const StationName& name() const noexcept;
+
+    /**
+     * @brief    band — read the target RF band.
+     *
+     * @dname    band
+     * @return   Dab or Fm band selector.
+     * @pubstate reads band_.
+     */
     [[nodiscard]] TunerBand band() const noexcept;
+
+    /**
+     * @brief    dabFreqIndex — read the Band III ensemble index.
+     *
+     * @dname    dabFreqIndex
+     * @return   Ensemble index 0–37.
+     * @pubstate reads dabFreqIndex_.
+     */
     [[nodiscard]] std::uint8_t dabFreqIndex() const noexcept;
+
+    /**
+     * @brief    dabServiceId — read optional DAB service id for play().
+     *
+     * @dname    dabServiceId
+     * @return   Service id when stored, otherwise empty.
+     * @pubstate reads dabServiceId_.
+     */
     [[nodiscard]] std::optional<std::uint32_t> dabServiceId() const noexcept;
+
+    /**
+     * @brief    dabComponentId — read optional DAB component id for play().
+     *
+     * @dname    dabComponentId
+     * @return   Component id when stored, otherwise empty.
+     * @pubstate reads dabComponentId_.
+     */
     [[nodiscard]] std::optional<std::uint32_t> dabComponentId() const noexcept;
+
+    /**
+     * @brief    fmFrequency — read FM centre frequency when band is Fm.
+     *
+     * @dname    fmFrequency
+     * @return   Frequency when stored, otherwise empty.
+     * @pubstate reads fmFrequency_.
+     */
     [[nodiscard]] std::optional<FrequencyKHz> fmFrequency() const noexcept;
+
+    /**
+     * @brief    presetSlot — read optional hardware preset button slot.
+     *
+     * @dname    presetSlot
+     * @return   Preset slot when assigned, otherwise empty.
+     * @pubstate reads presetSlot_.
+     */
     [[nodiscard]] std::optional<PresetSlot> presetSlot() const noexcept;
 
     /**